The overall goal to be pursued in the proposed research activities is to develop more specific and, at the same time, more sensitive non-invasive procedures in the diagnosis of peripheral arterial occlusive disease. Specifically, animal experiments are projected to study the effect of "small" artery perfusion impairment on several hemodynamic indices. This will represent a basis to improve the differential diagnosis between "small" and "large" artery occlusive disease. Clinical non-invasive hemodynamic studies will be continued with angiographic correlation. Both sources of information will be used in a specifically designed computer program which will enhance cross-correlation analysis of a multitude of inputs. A combination of computer and electronics based effort will be made to improve the signal to noise ratio in ultrasonic imaging. Finally, experiments are planned to investigate the effect of local mechanical properties on the pressure-flow relationship. All these sub-projects will serve as a basis for an improved diagnosis of peripheral arterial occlusive disease.